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USGS2002

Reproductive biology of four freshwater mussels (Bivalvia: Unionidae) endemic to eastern Gulf Coastal Plain drainages of Alabama, Florida, and Georgia

The reproductive biology and glochidial shell morphology of three federally endangered freshwater mussels, the fat threeridge, Amblema neislerii; Gulf moccasinshell, Medionidus penicillatus; and oval pigtoe, Pleurobema pyriforme; and one federally threatened mussel, the purple bankclimber, Elliptoideus sloatianus, were studied from May 1995 to June 1997 in the Apalachicola, Flint, and Ochlockonee river drainages of Florida and Georgia. Gravid A. neislerii were found in early June. Laboratory experiments indicated that five fish species served as hosts: weed shiner, Notropis texanus; bluegill, Lepomis macrochirus; redear sunfish, L. microlophus; largemouth bass, Micropterus salmoides; and blackbanded darter, Percina nigrofasciata. Elliptoideus sloatianus were found gravid from late February through mid-April. None of the 14 fish species exposed to E. sloatianus glochidia resulted in the identification of a primary host fish. Medionidus penicillatus were found gravid during September, November, March, and April. The brown darter, Etheostoma edwini, and blackbanded darter, Percina nigrofasciata, were identified as primary host fishes for M. penicillatus. Pleurobema pyriforme were found gravid from March through July. Only the sailfin shiner, Pleronotropis hypsehpterus, was identified as a primary host fish for P. pyriforme. Glochidial shell morphology of A. neislerii, M. penicillatus, and P. pyriforme were similar to other species in their respective genera. The glochidia of the monotypic species E. sloatianus were morphologically most similar to Epioblasma brevidens and E. capsaeformis.

American Malacological Bulletin↗

USGS2011

Nine endangered taxa, one recovering ecosystem: Identifying common ground for recovery on Santa Cruz Island, California

It is not uncommon to have several rare and listed taxa occupying habitats in one landscape or management area where conservation amounts to defense against the possibility of further loss. It is uncommon and extremely exciting, however, to have several listed taxa occupying one island that is managed cooperatively for conservation and recovery. On Santa Cruz Island, the largest of the northern California island group in the Santa Barbara Channel, we have a golden opportunity to marry ecological knowledge and institutional "good will" in a field test of holistic rare plant conservation. Here, the last feral livestock have been removed, active weed control is underway, and management is focused on understanding and demonstrating system response to conservation management. Yet funding limitations still exist and we need to plan the most fiscally conservative and marketable approach to rare plant restoration. We still experience the tension between desirable quick results and the ecological pace of system recovery. Therefore, our research has focused on identifying fundamental constraints on species recovery at individual, demographic, habitat, and ecosystem levels, and then developing suites of actions that might be taken across taxa and landscapes. At the same time, we seek a performance middle ground that balances an institutional need for quick demonstration of hands-on positive results with a contrasting approach that allows ecosystem recovery to facilitate species recovery in the long term. We find that constraints vary across breeding systems, life-histories, and island locations. We take a hybrid approach in which we identify several actions that we can take now to enhance population size or habitat occupancy for some taxa by active restoration, while allowing others to recover at the pace of ecosystem change. We make our recommendations on the basis of data we have collected over the last decade, so that management is firmly grounded in ecological observation.

California↗

USGS2012

Survey of roadside alien plants in Hawai`i Volcanoes National Park and adjacent residential areas 2001-2005

The sides of all paved roads of Hawai`i Volcanoes National Park (HAVO) were surveyed on foot in 2001 to 2005, and the roadside presence of 240 target invasive and potentially invasive alien plant species was recorded in mile-long increments. Buffer zones 5–10 miles (8–16 km) long along Highway 11 on either side of the Kīlauea and Kahuku Units of the park, as well as Wright Road that passed by the disjunct `Ōla`a Tract Unit, were included in the survey. Highway 11 is the primary road through the park and a major island thoroughfare. Three residential subdivisions adjacent to the park were similarly surveyed in 0.5–1 mile (0.8–1.6 km) intervals in 2003, and data were analyzed separately. Two roads to the east and northeast were also surveyed, but data from these disjunct areas were analyzed separately from park roads. In total, 174 of the target alien species were observed along HAVO roads and buffers, exclusive of residential areas, and the mean number of target aliens per mile surveyed was 20.6. Highway 11 and its buffer zones had the highest mean number of target alien plants per mile (26.7) of all park roads, and the Mauna Loa Strip Road had the lowest mean (11.7). Segments of Highway 11 adjacent to HAVO and Wright Road next to `Ōla`a Tract had mean numbers of target alien per mile (24–47) higher than those of any internal road. Alien plant frequencies were summarized for each road in HAVO. Fifteen new records of vascular plants for HAVO were observed and collected along park roads. An additional 28 alien plant species not known from HAVO were observed along the buffer segments of Highway 11 adjacent to the park. Within the adjacent residential subdivisions, 65 target alien plant species were sighted along roadsides. At least 15 potentially invasive species not currently found within HAVO were observed along residential roads, and several other species found there have been previously eliminated from the park or controlled to remnant populations. Data collected from this survey can be used by the park and other landowners to help detect and manage invasive plant species that threaten the natural resources of their lands, and survey findings will inform managers of threats from alien species established along corridors beyond park boundaries. Recommendations were made for refining the list of incipient invasive plant species to search for near the park and for the repetition of periodic roadside weed surveys in the park.

Hawaii↗

USGS2010

Appraising U.S. Geological Survey science records

The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center has legislative charters to preserve and make accessible land remote sensing records important to the United States. This essay explains the appraisal process developed by EROS to ensure the science records it holds and those offered to it align with those charters. The justifications behind the questions employed to weed and to complement the EROS archive are explained along with the literature reviewed supporting their inclusion. Appraisal results are listed by individual collection and include the recommendations accepted by EROS management.

Archival Issues↗

USGS1983

Evaluating environmental and economic consequences of alternative pest management strategies: results of modeling workshops

The U.S. Environmental Protection Agency (EPA) needs a comprehensive method to evaluate the human health and environmental effects of alternative agricultural pest management strategies. This project explored the utility of Adaptive Environmental Assessment (AEA) techniques for meeting this need. The project objectives were to produce models for environmental impact analysis, improve communications, identify research needs and data requirements, and demonstrate a process for resolving conflicts. The project was structured around the construction (in an initial 2 1/2-day workshop) and examination (in a second 2 1/2-day workshop) of a simulation model of a corn agroecosystem. The model conceptualized at the first workshop simulates the effect of corn agrecosystem decisions on crop production, economic returns, and environmental indicators. The model is composed of five interacting submodels: 1) a Production Strategies submodel which makes decisions concerning tillage, planting, fertilizer and pesticide applications, and harvest; 2) a Hydrology/Chemical Transport submodel which represents soil hydrology, erosion, and concentrations of fertilizers and pesticides in the soil, runoff, surface waters, and percolation; 3) a Vegetation submodel which simulates growth of agricultural crops (corns and soybeans) and weeds; 4) a Pests submodel which calculates pest population levels and resulting crop damage; and 5) an Environmental Effects submodel which calculates indicators of potential fish kills, human health effects, and wildlife habitat. The most persistent data gaps encountered in quantifying the model were coefficients to relate environmental consequences to alternative pest management strategies. While the model developed in the project is not yet accurate enough to be used for real-world decisions about the use of pesticides on corn, it does contain the basic structure upon which such a model could be built. More importantly at this stage of development, the project has shown that very complex systems can be modeled in short periods of time and that the process of building such models increases understanding among disciplinary specialists and between diverse institutional interests. This process can be useful to EPA as the agency cooperates with other institutions to meet its responsibilities in less costly ways. Activities at the second 2 1/2-day workshop included a review of the model, incorporation of necessary corrections, simulation of policy scenarios, and examination of techniques to address remaining institutional conflicts. Participants were divided into three groups representing environmental, production or industry, and regulatory interests. Each group developed scenarios that would be most appealing to their particular interest and the scenarios were simulated by the agroecosystem computer model. Negotiators from each of the interest groups decided whether a hypothetical herbicide should be relabeled and if certain restrictions should be imposed on its use. Other participants functioned as experts and consultants on caucus teams. A solution to the hypothetical problem was successfully negotiated. Workshop participants and project staff agreed that the model and processes developed during the project should be used in training students, extension specialists, farmers, researchers, and chemical producers in collaborative problem solving methods. More productive research can be planned, and more realistic models of complex systems can be built in this way. More importantly, greater trust of decisionmakers in computer models, better understanding by technical experts about disciplines other than their own, and improved cooperation between institutional interests can be achieved. This trust, understanding, and cooperation are critical ingredients in solving problems that are too complex to be resolved by independent disciplinary activity and unilateral decision authority.

Report↗

USGS2014

Changes in Mauna Kea Dry Forest Structure 2000-2014

Changes in the structure of the subalpine vegetation of Palila Critical Habitat on the southwestern slope of Mauna Kea Volcano, Hawai‘i, were analyzed using 12 metrics of change in māmane (Sophora chrysophylla) and naio (Myoporum sandwicense) trees surveyed on plots in 2000 and 2014. These two dominant species were analyzed separately, and changes in their structure indicated changes in the forest’s health. There was a significant increase in māmane minimum crown height (indicating a higher ungulate “browse line”), canopy area, canopy volume, percentage of trees with ungulate damage, and percentage of dead trees. No significant changes were observed in māmane maximum crown height, proportion of plots with trees, sapling density, proportion of plots with saplings, or the height distribution of trees. The only significant positive change was for māmane tree density. Significantly negative changes were observed for naio minimum crown height, tree height, canopy area, canopy volume, and percentage of dead trees. No significant changes were observed in naio tree density, proportion of plots with trees, proportion of plots with saplings, or percentage of trees with ungulate damage. Significantly positive changes were observed in naio sapling density and the height distribution of trees. There was also a significant increase in the proportion of māmane vs. naio trees in the survey area. The survey methods did not allow us to distinguish among potential factors driving these changes for metrics other than the percentage of trees with ungulate damage. Continued ungulate browsing and prolonged drought are likely the factors contributing most to the observed changes in vegetation, but tree disease or insect infestation of māmane, or naio, and competition from alien grasses and other weeds could also be causing or exacerbating the impacts to the forest. Although māmane tree density has increased since 2000, this study also demonstrates that efforts by managers to remove sheep (Ovis spp.) from Palila Critical Habitat have not overcome the ability of sheep to continue to damage māmane trees and impede restoration of the vegetation.

Hawaii↗

USGS2010

Herbicide treatment of invasive Vinca major growing with endangered Galium buxifolium, an island endemic

Galium buxifolium E. Greene [Rubiaceae] (sea-cliff bedstraw) is a small shrub restricted to San Miguel and Santa Cruz Islands, in the California Channel Islands. Almost all of the 26 known populations grow on vertical north-facing sea cliffs in native scrub, sandwiched between the sea below and non-native annual grasslands on the terraces above. A notable exception is a popula?tion at Pelican Bay on Santa Cruz Island, growing on the cliff and on thin terrace soils above the cliff in a stand of coastal bluff scrub that is recovering from more than a century of sheep grazing (Figure 1). Ironically, this stand is near the location of the historic Eaton Resort, a charismatic inn frequented by Hollywood glitterati in the early 1900s. Several landscape ornamentals planted there persist today in the area of the Galium population. Italian stone pine (Pinus pinaea) and eucalyptus (Eucalyptus spp.) tower over the site while the invasive groundcover Vinca major L. [Apocynaceae] (greater periwinkle) forms dense mats at the cliff edge that are spreading into the developing native plant stand. Wherever the Galium is found it is intermixed with other native scrub plants in dense communities on moist ocean bluffs. Historic notes and herbarium collections indicate that it may have been more widespread on nearshore terraces adjacent to sea-cliff populations before conversion to grassland. Since Pelican Bay is the only site that we know of where Galium is spreading onto the nearby terrace, we wanted to know whether the Vinca posed a roadblock to upslope population expansion. In 2005 we mapped Vinca and Galium at the site. We also measured Galium individuals to see where the smaller, younger plants were to better understand where the population is expanding. We observed that 1) both the Galium and the Vinca appear to be spreading from the cliff face upslope onto a series of rock outcrops, stone walls and benches, 2) the native scrub community is recovering at the site and 3) the Vinca appears to be moving into the native scrub where it overtops small plants, including those Galium in the smallest size classes. This observed pattern of Vinca displacement of native vegetation has been noted in other places, where it is treated as an invasive weed. We concluded that Vinca may pose a threat to the expansion of both the native scrub and the Galium population that it supports. Therefore, we worked with the US Fish and Wildlife Service and others to develop a research project investigating 1) best techniques for killing Vinca within the boundaries of an endangered plant population and 2) demographic response of Galium to the treatment. Our intent is to push Vinca back to the vertical cliff face to give the natives a chance to establish a vigorous stand. Our conservation goal is to encourage natural establishment of new Galium plants on the terrace along with expansion of the native coastal bluff scrub and Galium population. Our immediate treatment objective is to reduce live Vinca cover by 90 % on the accessible upslope portions of the habitat. Our recovery objective is no net loss of Galium plants 2006-2016.

California↗

USGS2009

Twenty-three years of vegetation change in a fly-ash leachate impacted meadow

1. Blag Slough, located in Indiana Dunes National Lakeshore, has received leachates from nearby fly-ash ponds for 13 years (1967-1980). We have monitored vegetation and sediment of Blag Slough since 1982, two years after the sealing of the fly-ash ponds and one year after the substrate was first exposed. The pH of the soil has increased one order of magnitude from 3.0 to 4.0 over the 23 years (1982-2005). If the pH further increases the solubility of many heavy metals will decrease, except for arsenic. We provide evidence that boron and zinc were bioaccumulating in the leaves of woody plants in 1984. The ratio of leaf concentration and soil concentration of aluminum suggests this element was not bioaccumulating in woody plants in 1984. 2. Soil concentrations of iron, aluminum, arsenic, and strontium were higher nearest the fly-ash ponds in 2005. The southwest corner of Blag Slough and middle position of transect X had the highest elevated levels of these metals and correlated with the occurrence of mixed spikerush association (dominated by Eleocharis olivacea). 3. Only a few exotic species occurred in the Blag Slough. Common reed (Phragmites australis) was among such species that occurred in three large clones. Other exotic species included dandelion (Taraxacum officinale), mullein (Verbascum thapsis), Jerusalem oak goosefoot (Chenopodium botrys), and sheep sorrel (Rumex acetosella). Ruderal species have occurred including thistle (Cirsium spp.), fire weed (Erechtites hieracifolium), and horseweed (Conyza canadensis). While occasional cattail (Typha) have been sampled and mapped in Blag Slough they have never persisted for very long. 4. Species richness leveled off between 1991 and 2005, except for Transect X that had a peak in 1986-7. After an extreme rainfall event in August 18, 1990, Transect V had an average water depth of 0.70 cm, W had 7.1 cm, and X had 26.90 cm. Richness in Transect X declined to a low level in 1990 and 1991 after the extreme flooding event because this transect had the deepest surface water. 5. Typical late successional vegetation associations developed since 1991 include blue joint grass (Calamagrostis canadensis) and buttonbush (Cephalanthus occidentalis), but large areas consist of disturbance-dependent mosaics of rush (Juncus effusus) and other species. The large expanses of woolly sedge (Scirpus cyperinus) that dominated in the 1980’s was replaced by rush. 6. Late-successional associations (Glyceria canadensis and Calamagrostis canadensis) were closer to the wetland edge compared to the other associations after the dewatering. This pattern occurred because wet meadow vegetation persisted at the wetland edge during the period of industrial flooding, but since then these associations expanded greatly into the north half of Blag Slough. 7. Richness, diversity, and floristic quality index (FQI) increased with time at the plot, association, association trajectories, and wetland levels; whereas mean conservatism scores (mean C), the basis of FQI calculation, decreased in time. The high C values, assigned to coastal plain disjunct species and shrubs by judgment of botanists based on their empirical xii experience including regional or state level plant conservation designations are largely responsible for the contradicted trend between FQI and C. Such contradiction highlights a problem with the subjective assignment of C values, and thus the inadequacy of application of FQI in these wetland systems. 8. Occurrence of interveinal clearing in winged sumac (Rhus copallina), late boneset (Eupatorium serotinum), and black dewberry (Rubus occidentalis) suggest a potential phytotoxicity by heavy metals. However, cause-effect relationship between the metals and the plants are yet to be investigated. Nevertheless, boron and zinc accumulation ratios in leaves of woody plants (Betula populifolia, Populus tremuloides, Rhus copallina, and Rubus sp.) in 1984 suggest that boron and zinc were bioaccumulating in those species. Known toxicity effects of aluminum suggest that plants with vein clearing may be experiencing toxic effects of aluminum despite leaf concentrations 58 to 193 ppm. 9. In a greenhouse experiment, rye (Secale cereale) and radish (Raphanus sativus) germinated poorly in the sediments from Blag Slough having high concentrations of heavy metals (ZN, Mn, B, and NH4+) compared to potting soil. However, rye and radish plants grown in Blag Slough soil had shorter shoots and roots, lower root and shoot mass, and lower root to shoot mass ratios compared to plants grown in potting soil. These results suggest some effect of the soil constituents on rye and radish growth. 10. Positive signs in the recovery of Blag Slough include the increase in soil pH, the increasing dominance of late successional grasses, and the establishment of wetland zonation relative to seasonal water depth. Some areas of Blag Slough near the fly-ash ponds that continue to have high concentrations of heavy metals continue to be devoid of vegetation or are dominated by early successional species such as green spikerush. Localized heavy metal concentrations, evidence for zinc and boron bioaccumulation in 1984, vein clearing that persists today, effects of soil on rye and racish growth, and slow succession in the southern portion of Blag Slough suggest further toxicity study is necessary to better assess the impacts on this wetland ecosystem and identify restoration actions.

Indiana↗

USGS1973

Changes in floodflow characteristics of a rectified channel caused by vegetation, Jackson, Mississippi

Extreme changes in velocity, stage, and Manning's roughness coefficient, n , were observed during the first year after canalization of Hanging Moss Creek at Jackson, Miss. Additional changes were observed during the following 8 years. The channel, constructed during the summer of 1963, had a 50-foot-wide bottom, 2:1 side slopes, and 12-foot depth. In March 1964, average velocities of 7.8 feet per second were measured at a 5 1/2-foot depth in the clean channel and Manning's n was computed to be 0.022. In October 1964 the average velocity was 3.2 fps at a 5 1/2-foot depth and Manning's n was 0.045. The channel was then lined with fairly thick vegetation consisting of small willows, weeds, and grass. In October 1970 (summer foliage existing) the average velocity was 2.0 fps at a 5 1/2-foot depth and Manning's n was 0.07. Willow trees, 8 to 10 feet high, then lined the channel. In March 1971 (barren foliage), Manning's n was 0.05. In March 1972 (barren foliage), Manning's n was increased to 0.07. These observations indicate that the commonly used values of Manning's n for channel rectification (0.02-0.03) are low and that the carrying capacity of earthen channels may be reduced 50 percent as a result of only 1 year's growth of vegetation and 70 percent as a result of 8 year's growth. The carrying capacity during summer foliage is approximately two-thirds the carrying capacity during barren winter foliage.

Mississippi↗

USGS2011

Chapter 10: Occurrence of non-native invasive plants: The role of anthropogenic features

The invasion of non-native plants in the Wyoming Basins Ecoregional Assessment (WBEA) area is a major economic and ecological stress, with invasions thought to be hastened by energy developments. Given the potential impacts of nonnative invasive plants and the rapid changes in land use in the WBEA, broad-scale assessments and predictive models of nonnative invasive plant distribution are needed. Using this information, the current extent of populations for targeting treatment and monitoring can be identified, the habitat affinities for forecasting where weeds may establish next determined, and the responses to individual human disturbances (such as energy developments) predicted. To address these needs, we conducted vegetation surveys across the WBEA area at 317 individual survey blocks (five plots per survey block) during the summers of 2005 and 2006. Survey blocks were stratified by both human disturbance and habitat productivity; in each of five plots per survey block the occurrence of 23 common nonnative invasive plants was recorded during early and late season surveys. Here, we report on the four most common invasive plants, crested wheatgrass ( Agropyron cristatum ), cheatgrass ( Bromus tectorum ), halogeton ( Halogeton glomeratus ), and Russian thistle ( Salsola spp. ). Occurrence models were generated for each species using random-effects logistic regression to account for nesting of plots within sample sites. Predictors of occupancy included local habitat, abiotic condition, and distance to anthropogenic features. Although occurrences of all four invasive plants were affected by habitat, abiotic, and anthropogenic factors, cheatgrass and Russian thistle were most strongly associated with anthropogenic disturbance, primarily major roads and energy well sites. We assessed relationships between environmental and anthropogenic predictors and species occurrences to identify the major factors affecting current species distribution, examined shape of the response in occurrence in relation to proximity to individual anthropogenic disturbances, and provided spatial predictions of the locations where invasive plants are most likely to occur.

Wyoming↗

USGS1999

Septoria hodgesii sp. nov.: A potential biocontrol agent for Myrica faya in Hawai‘i

Septoria hodgesii sp. nov. is described. This fungus is a common leaf pathogen of Myrica cerifera in the southeastern U.S., where it usually has been identified as S. myricae . It also has been shown by artificial inoculation to be pathogenic on M. faya , an introduced forest weed in Hawai'i. Comparison of S. hodgesii with the types of S. myricae , from M. cerifera and S. myricata , from M. gale , showes it to be distinct from both species.

Hawai'i↗

USGS1997

Status, ecology, and management of the invasive plant, Miconia calvescens DC (Melastomataceae) in the Hawaiian islands

Miconia calvescens (Melastomataceae), native to montane forests of the neotropics, has now invaded wet forests of both the Society and Hawaiian Islands. This tree, which grows up to 15 m tall, is potentially the most invasive and damaging weed of rainforests of Pacific islands. In moist conditions, it grows rapidly, tolerates shade, and produces abundant seed that is effectively dispersed by birds and accumulates in a large, persistent soil seed-bank. Introduced to the Hawaiian Islands in 1961, M. calvescens appears to threaten much of the biological diversity in native forests receiving 1800–2000 mm or more annual precipitation. Currently, M. calvescens is found on 4 Hawaiian islands— Hawaii, Maui, Oahu, and Kauai. Widespread awareness of this invader began in the early 1990s. Although biological control is being pursued, conventional control techniques (mechanical and chemical) to contain and eradicate it locally are underway.

Hawaii↗

USGS2017

Monitoring Hawaiian biodiversity: Pilot study to assess changes to forest birds and their habitat

Biological diversity, or biodiversity, is the variety and abundance of species in a defined area, and is one of the oldest and most basic descriptions of biological communities. Understanding how populations and communities are structured and change over space and time in response to internal and external forces is a management priority. Effective management practices and conservation strategies depend on our understanding of the relationship between changes in biodiversity and ecological drivers such as invasive species, land use and climate change. To demonstrate how changes in biodiversity may be monitored over a large (400 km2) tract of native forest habitat, we compared bird and plant community composition and structure in an upper montane region of Hawai‘i Island originally surveyed in 1977 as part of the Hawai‘i Forest Bird Survey (Scott et al. 1986) with a comprehensive sample of the same region in 2015. Our findings suggest that across a region spanning an elevation range of 600 to 2,000 m considerable changes occurred in the plant and bird communities between 1977 and 2015. Endemic and indigenous plants species richness (i.e., total number of species) decreased dramatically in the low and middle elevations below an invasive weed front, whereas naturalized plant species richness did not change between the two periods at any elevation. Endemic bird abundance decreased and two species were lost in the lower elevations (< 1,100 m) between 1977 and 2015, while naturalized bird abundance and the numbers of species increased in the same area. In addition to changes in community composition, the structure of the forest showed evidence of changes in dominant and sub-dominant tree canopy cover, shrub and herbaceous cover, dominant tree canopy height, and matted fern cover. Biodiversity monitoring helps to define specific conservation targets and to measure progress towards reaching those targets. It is difficult to ascribe causative factors to a change in biodiversity without directly manipulating the environment. Forest habitat in a variety of settings (i.e., islands and regions with differing land-use histories and elevation ranges), however, can provide opportunities to evaluate the influence of ecological drivers. Declines in native bird biodiversity in low-elevation areas may be attributed to invasive species as land use and climate conditions have remained relatively similar over the 40-year period. Thus, the shift from an endemic-naturalized co-dominated community in 1977 to one dominated by naturalized, alien birds in 2015, and reduction in native bird abundance over that period, may reflect increasing dominance by naturalized plants within this forested area. Inferences drawn from analyses of region-wide surveys, especially with replicate datasets, will facilitate the identification of broad-scale changes in biodiversity, and provide a needed current datum in Hawaiian plant and bird biodiversity monitoring.

Hawaii↗

USGS2001

Interactions between fire and invasive plants in temperate grasslands of North America

A substantial number of invasive grasses, forbs and woody plants have invaded temperate grasslands in North America. Among the invading species are winter annuals, biennials, cool-season perennials, warm-season perennials, vines, shrubs, and trees. Many of these species have been deliberately introduced and widely planted; some are still used for range improvement, pastures, lawns, and as ornamentals, though many are listed as state or federal noxious weeds. Others have been greatly facilitated by widespread land disturbance. Historically, fire has been a major selective force in the evolution of temperate grasslands. Further, prescribed fire is commonly used as a method of ecological management for native grassland communities as well as in conjunction with restoration efforts. Within this context, it is important to understand how invasive species will interact with natural and prescribed fire regimes. In this paper, we consider what is known about how exotic species that invade temperate grasslands relate to fire. The primary issues addressed for each species are (1) Does fire appear to enhance colonization? (2) To what degree does fire affect the survival of plants? (3) Are plants that are burned able to regrow following fire and, if so, how rapidly can they recover? (4) How important is competition with native species to the response to fire? and (5) What effect does an invasive species have on the characteristics of the fire regime? For many species, results are preliminary, incomplete, or inconsistent among studies. For this reason, many of the conclusions drawn for individual species must be considered preliminary. Based on analyses of individual species, a conceptual framework is presented for considering how invasive plants may interact with fire when they invade an ecosystem. The major categories of influences are the native community, the fire regime, growth conditions for both invasive and native species, and influences that disturbances, human impacts, and landscape characteristics have had in the past and will have in the future. The examples considered in this paper provide support for a few, tentative generalizations. First, among our current worst invaders of temperate grasslands, adaptation to fire is quite variable. Some species are not well adapted to burning and can be easily eliminated; other species are better adapted but can still be eliminated if fire occurs during periods of particular vulnerability and/or at high frequency. There is a set of species that is extremely well adapted to fire and will not be eliminated through burning alone. Second, competitive interactions with native species play a crucial role in the success of nonnative invaders. In cases where differential burn responses between invasive and native species can be exploited, and adequate populations of native dominant species are present, fire can sometimes tip the competitive balance away from invasives. Third, there are a few invasive species that have exceptional attributes and for which there are no easy solutions. The ability of cheatgrass ( Bromus tectorum ) to enhance fire, the ability of Chinese tallow ( Triadica sebifera ) to suppress fire, and the ability of leafy spurge ( Euphorbia esula ) to resprout from repeated injury make these species exceptional threats to native diversity. Finally, the available information for many invasive species is very incomplete, partic- ularly with regard to how fire affects competitive interactions with the native community. There is much more we need to know if we are to consistently predict how invasive species will respond to fire and how burning can best be used to manage for natural diversity.

Conference Paper↗

USGS2020

Hawaiian hoary bat (Lasiurus cinereus semotus) acoustic monitoring at Hawaii Army National Guard (HIARNG) installations statewide

Acoustic sampling for occurrence of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus) was conducted at 18 “long-term” acoustic monitoring stations on 12 Hawai‘i Army National Guard (HIARNG) installations across the islands of Hawai‘i, Maui, Moloka‘i, O‘ahu, and Kaua‘i between 2012 and 2018. Bats were confirmed as present at 10 of these installations: Kealakekua Armory, Keaukaha Military Reservation (KMR), Hanapēpe Armory, Kekaha Firing Range (KFR), Pu‘unēnē Training Facility, Ukumehame Firing Range (UFR), Kaunakakai Armory, Bellows Regional Training Institute, Kalaeloa, Barber’s Point, and the 487th Military Parking Facility, Wahiawā. Seasonal frequency of bat detection was similar to previous acoustic studies for the islands of Hawai‘i, Maui, and O‘ahu. Hawaiian hoary bats were recorded at HIARNG installations during periods of pregnancy, lactation, and pup fledging. Our acoustic sampling did not record bat vocalizations at Fort Ruger and Waiawa Armory. Foraging activity was observed at nine acoustic monitoring stations on the islands of Hawai‘i, Kaua‘i, O‘ahu, and Maui. No foraging activity was observed on Moloka‘i and a single station on O‘ahu recorded one feeding buzz in September 2017 at Kalaeloa, Barber’s Point. Within-night detections showed bat activity was mostly confined to the first six hours of the night but was also variable among stations. In addition to long-term bat acoustic monitoring at HIARNG installations, Hawaiian hoary bat insect prey sampling with paired acoustic monitoring was conducted at KMR on Hawai‘i Island from May through August 2018. Insect abundance and bat activity were sampled within areas where goats and sheep were used to control weeds to determine if grazing by these ungulates attract and support potential prey for the insectivorous Hawaiian hoary bat. The assessment focused on types of flies that are often associated with livestock (muscoid flies, including house flies [Muscidae], blow flies [Calliphoridae], flesh flies [Sarcophagidae], and biting midges [Ceratopogonidae]), and moths that may be impacted by changes in the availability of grass. Insect abundance was found to vary in both space and time across the study area, with numbers of muscoid flies and biting midges increasing in the presence of livestock at some stations. Although these insects appeared to respond to livestock grazing in some instances, we did not find statistically significant responses in bat foraging as measured by echolocation activity between grazed stations and the ungrazed reference station. Thus, we found no evidence that suggested bats are drawn to foraging resources in grazed areas. This result may be influenced by several factors, including the size of Hawaiian hoary bat foraging ranges compared to the scale of study area, the type of ungulate and their dung, and the timing of insect activity. Hawaiian hoary bats use KMR and forage seasonally as evidenced by long-term acoustic studies and their presence in the ungulate grazing areas; however, the relatively small size of the ungulate herd and the area that they graze may not be able to support enough prey to have a significant influence on bat foraging rates.

Hawaii↗

USGS2020

Appendix C: Interim report on subtask focused on resampling historic Kennedy/ITD plots for RP-284

In October 2019, an Idaho Transportation Department (ITD) Cooperative Transportation Research Program award was made to Boise State University in partnership with the U.S. Geological Survey to investigate the use of weed-suppressive bacteria (Pseudomonas fluorescens strain ACK55) with preemergent herbicides (imazapic and indaziflam) to reduce exotic annual grasses (cheatgrass, medusahead) on ITD right-of-ways. The work includes a subtask in which ITD right-of-ways treated with ACK55 by Dr. Ann Kennedy 4-5 years previously (2017 report; ITD-RP-258) were resampled in summer 2020, focusing only on ACK55 and not the herbicides (which are tested separately and will be reported on in the future). The 2020 sampling protocol was similar but more intensive than the ITD-RP-258. There were no differences in annual grasses on areas sprayed with ACK55 and nearby untreated areas.

Idaho↗

USGS1941

Attwater's prairie-chicken-its life history and management

Attwater's prairie chicken, a characteristic bird of the Texas coastal prairie, is closely related to the now extinct heath-hen of northeastern North America. Once abundant in an area extending from the coastal tall-grass prairies of southwestern Louisiana and Texas west and south to near Port Isabel, it has decreased in numbers as man has exploited its habitat, until now it is threatened with the same fate as that of the heath-hen. Important factors limiting the numbers of the bird include excessive or persistent rainfall during the nesting season, heavy grazing, excessive pasture burning, agricultural operations, and overshooting. Management will usually involve protection from excessive killing, improvement of food and cover, and control of predators and of the kill by hunters. Responsibility for this rests with the landowner. Optimum prairie chicken range apparently consists of well-drained grassland, with some weeds or shrubs, the cover varying in density from light to heavy; and with surface water available in summer; diversification within the grassland type is essential. In the absence of ample refuges for the species, probably all other favorable factors together will fail to save Attwater's prairie chicken from extinction. This number continues the series of the North American Fauna issued by the Bureau of Biological Survey, of the United States Department of Agriculture, prior to its transfer and consolidation with the Bureau of Fisheries on June 30, 1940, to form the Fish and Wildlife Service, in the Department of the Interior.

North American Fauna↗

USGS1974

Preliminary report on geology along Atlantic continental margin of northeastern United States

The U.S. Geological Survey is conducting a geologic and geophysical study of the northeastern United States outer continental shelf and the adjacent slope from Georges Bank to Cape Hatteras. The study also includes the adjacent coastal plain because it is a more accessible extension of the shelf. The total study area is about 324,000 sq km, of which the shelf and slope constitute about 181,000 sq km and the coastal plain constitutes 143,000 sq km. The shelf width ranges from about 30 km at Cape Hatteras to about 195 km off Raritan Bay and on Georges Bank. Analyses of bottom samples make if possible to construct a preliminary geologic map of the shelf and slope to a water depth of 2,000 m. The oldest beds cropping out in the submarine canyons and on the slope are of early Late Cretaceous age. Beds of Early Cretaceous and Jurassic age are present in deep wells onshore and probably are present beneath the shelf in the area of this study. Such beds are reported beneath the Scotian shelf on the northeast where they include limestone, salt, and anhydrite. Preliminary conclusions suggest a considerably thicker Mesozoic sedimentary sequence than has been described previously. The region is large; the sedimentary wedge is thick; structures seem favorable; and the hydrocarbon potential may be considerable.

Atlantic continental margin↗